CAT24C256 256 kb I2C CMOS Serial EEPROM Description The CAT24C256 is a 256 kb Serial CMOS EEPROM, internally organized as 32,768 words of 8 bits each. It features a 64−byte page write buffer and supports both the Standard (100 kHz) as well as Fast (400 kHz) I2C protocol. Write operations can be inhibited by taking the WP pin High (this protects the entire memory). External address pins make it possible to address up to eight CAT24C256 devices on the same bus. http://onsemi.com SOIC−8 W SUFFIX CASE 751BD TDFN−8 ZD2 SUFFIX CASE 511AM SOIC−8 X SUFFIX CASE 751BE Features • • • • • • • • • • • Supports Standard and Fast I2C Protocol 1.8 V to 5.5 V Supply Voltage Range 64−Byte Page Write Buffer Hardware Write Protection for Entire Memory Schmitt Triggers and Noise Suppression Filters on I2C Bus Inputs (SCL and SDA) Low Power CMOS Technology 1,000,000 Program/Erase Cycles 100 Year Data Retention Industrial and Extended Temperature Range PDIP, SOIC, TSSOP and TDFN 8−lead Packages This Device is Pb−Free, Halogen Free/BFR Free, and RoHS Compliant PDIP−8 L SUFFIX CASE 646AA PIN CONFIGURATION A0 1 VCC A1 WP A2 SCL VSS SDA PDIP (L), SOIC (W, X), TSSOP (Y), TDFN (ZD2) VCC For the location of Pin 1, please consult the corresponding package drawing. SCL CAT24C256 A2, A1, A0 TSSOP−8 Y SUFFIX CASE 948AL PIN FUNCTION SDA Pin Name WP A0, A1, A2 Function Device Address SDA Serial Data VSS SCL Serial Clock Figure 1. Functional Symbol WP Write Protect VCC Power Supply VSS Ground ORDERING INFORMATION See detailed ordering and shipping information in the package dimensions section on page 14 of this data sheet. © Semiconductor Components Industries, LLC, 2009 November, 2009 − Rev. 9 1 Publication Order Number: CAT24C256/D CAT24C256 Table 1. ABSOLUTE MAXIMUM RATINGS Parameters Ratings Units Storage Temperature –65 to +150 °C Voltage on any Pin with Respect to Ground (Note 1) –0.5 to +6.5 V Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. 1. The DC input voltage on any pin should not be lower than −0.5 V or higher than VCC + 0.5 V. During transitions, the voltage on any pin may undershoot to no less than −1.5 V or overshoot to no more than VCC + 1.5 V, for periods of less than 20 ns. Table 2. RELIABILITY CHARACTERISTICS (Note 2) Symbol Parameter NEND (Note 3) TDR Endurance Min Units 1,000,000 Program/Erase Cycles 100 Years Data Retention 2. These parameters are tested initially and after a design or process change that affects the parameter according to appropriate AEC−Q100 and JEDEC test methods. 3. Page Mode, VCC = 5 V, 25°C. Table 3. D.C. OPERATING CHARACTERISTICS (VCC = 1.8 V to 5.5 V, TA = −40°C to +125°C, unless otherwise specified.) Symbol Max Units ICCR Read Current Read, fSCL = 400 kHz 1 mA ICC Write Current Write, fSCL = 400 kHz 3 mA ISB Standby Current All I/O Pins at GND or VCC TA = −40°C to +85°C 1 mA TA = −40°C to +125°C 2 TA = −40°C to +85°C 1 IL Parameter Test Conditions I/O Pin Leakage Pin at GND or VCC Min TA = −40°C to +125°C mA 2 VIL Input Low Voltage −0.5 VCC x 0.3 V VIH Input High Voltage VCC x 0.7 VCC + 0.5 V VOL1 Output Low Voltage VCC ≥ 2.5 V, IOL = 3.0 mA 0.4 V VOL2 Output Low Voltage VCC < 2.5 V, IOL = 1.0 mA 0.2 V Table 4. PIN IMPEDANCE CHARACTERISTICS (VCC = 1.8 V to 5.5 V, TA = −40°C to +125°C, unless otherwise specified.) Symbol Parameter Conditions Max Units CIN (Note 4) SDA I/O Pin Capacitance VIN = 0 V 8 pF CIN (Note 4) Input Capacitance (other pins) VIN = 0 V 6 pF IWP (Note 5) WP Input Current (Product Revision C and higher) VIN < VIH, VCC = 5.5 V 130 mA VIN < VIH, VCC = 3.3 V 120 VIN < VIH, VCC = 1.8 V 80 VIN > VIH 1 4. These parameters are tested initially and after a design or process change that affects the parameter according to appropriate AEC−Q100 and JEDEC test methods. 5. When not driven, the WP pin is pulled down to GND internally. For improved noise immunity, the internal pull−down is relatively strong; therefore the external driver must be able to supply the pull−down current when attempting to drive the input HIGH. To conserve power, as the input level exceeds the trip point of the CMOS input buffer (~ 0.5 x VCC), the strong pull−down reverts to a weak current source. The variable WP input impedance is available only for Die Rev. C and higher. http://onsemi.com 2 CAT24C256 Table 5. A.C. CHARACTERISTICS (Note 6) (VCC = 1.8 V to 5.5 V, TA = −40°C to +125°C, unless otherwise specified.) Standard VCC = 1.8 V − 5.5 V Parameter Symbol FSCL tHD:STA Max Clock Frequency Min 100 START Condition Hold Time Max Fast−Plus (Note 9) VCC = 2.5 V − 5.5 V TA = −405C to +855C Min 400 Max Units 1,000 kHz 4 0.6 0.25 ms tLOW Low Period of SCL Clock 4.7 1.3 0.55 ms tHIGH High Period of SCL Clock 4 0.6 0.25 ms 4.7 0.6 0.25 ms tSU:STA START Condition Setup Time tHD:DAT Data In Hold Time 0 0 0 ms tSU:DAT Data In Setup Time 250 100 50 ns tR (Note 7) SDA and SCL Rise Time tF (Note 7) SDA and SCL Fall Time tSU:STO STOP Condition Setup Time tBUF Bus Free Time Between STOP and START tAA SCL Low to Data Out Valid tDH Data Out Hold Time Ti (Note 7) 1,000 300 300 300 100 ns 100 ns 4 0.6 0.25 ms 4.7 1.3 0.5 ms 3.5 100 0.9 100 Noise Pulse Filtered at SCL and SDA Inputs 100 0.50 50 100 ms ns 100 ns tSU:WP WP Setup Time 0 0 0 ms tHD:WP WP Hold Time 2.5 2.5 1 ms tWR tPU (Notes 7, 8) 6. 7. 8. 9. Min Fast VCC = 1.8 V − 5.5 V Write Cycle Time 5 5 Power-up to Ready Mode 1 1 0.1 5 ms 1 ms Test conditions according to “A.C. Test Conditions” table. Tested initially and after a design or process change that affects this parameter. tPU is the delay between the time VCC is stable and the device is ready to accept commands. Fast−Plus (1 MHz) speed class available for product revision “D”, identified by letter “D” marked on top of the package. Table 6. A.C. TEST CONDITIONS Input Levels 0.2 x VCC to 0.8 x VCC Input Rise and Fall Times ≤ 50 ns Input Reference Levels 0.3 x VCC, 0.7 x VCC Output Reference Levels 0.5 x VCC Output Load Current Source: IL = 3 mA (VCC ≥ 2.5 V); IL = 1 mA (VCC < 2.5 V); CL = 100 pF http://onsemi.com 3 CAT24C256 Power-On Reset (POR) The CAT24C256 Die Rev. C incorporates Power−On Reset (POR) circuitry which protects the internal logic against powering up in the wrong state. The device will power up into Standby mode after VCC exceeds the POR trigger level and will power down into Reset mode when VCC drops below the POR trigger level. This bi−directional POR behavior protects the device against brown−out failure, following a temporary loss of power. device pulls down the SDA line to ‘transmit’ a ‘0’ and releases it to ‘transmit’ a ‘1’. Data transfer may be initiated only when the bus is not busy (see A.C. Characteristics). During data transfer, the SDA line must remain stable while the SCL line is HIGH. An SDA transition while SCL is HIGH will be interpreted as a START or STOP condition (Figure 2). START The START condition precedes all commands. It consists of a HIGH to LOW transition on SDA while SCL is HIGH. The START acts as a ‘wake−up’ call to all receivers. Absent a START, a Slave will not respond to commands. Pin Description SCL: The Serial Clock input pin accepts the Serial Clock signal generated by the Master. SDA: The Serial Data I/O pin receives input data and transmits data stored in EEPROM. In transmit mode, this pin is open drain. Data is acquired on the positive edge, and is delivered on the negative edge of SCL. A0, A1 and A2: The Address pins accept the device address. These pins have on−chip pull−down resistors. WP: The Write Protect input pin inhibits all write operations, when pulled HIGH. This pin has an on−chip pull−down resistor. STOP The STOP condition completes all commands. It consists of a LOW to HIGH transition on SDA while SCL is HIGH. The STOP starts the internal Write cycle (when following a Write command) or sends the Slave into standby mode (when following a Read command). Device Addressing The Master initiates data transfer by creating a START condition on the bus. The Master then broadcasts an 8−bit serial Slave address. The first 4 bits of the Slave address are set to 1010, for normal Read/Write operations (Figure 3). The next 3 bits, A2, A1 and A0, select one of 8 possible Slave devices. The last bit, R/W, specifies whether a Read (1) or Write (0) operation is to be performed. Functional Description The CAT24C256 supports the Inter−Integrated Circuit (I2C) Bus data transmission protocol, which defines a device that sends data to the bus as a transmitter and a device receiving data as a receiver. Data flow is controlled by a Master device, which generates the serial clock and all START and STOP conditions. The CAT24C256 acts as a Slave device. Master and Slave alternate as either transmitter or receiver. Up to 8 devices may be connected to the bus as determined by the device address inputs A0, A1, and A2. Acknowledge After processing the Slave address, the Slave responds with an acknowledge (ACK) by pulling down the SDA line during the 9th clock cycle (Figure 4). The Slave will also acknowledge the byte address and every data byte presented in Write mode. In Read mode the Slave shifts out a data byte, and then releases the SDA line during the 9th clock cycle. If the Master acknowledges the data, then the Slave continues transmitting. The Master terminates the session by not acknowledging the last data byte (NoACK) and by sending a STOP to the Slave. Bus timing is illustrated in Figure 5. I2C Bus Protocol The I2C bus consists of two ‘wires’, SCL and SDA. The two wires are connected to the VCC supply via pull−up resistors. Master and Slave devices connect to the 2−wire bus via their respective SCL and SDA pins. The transmitting http://onsemi.com 4 CAT24C256 SCL SDA START CONDITION STOP CONDITION Figure 2. Start/Stop Timing 1 0 1 0 A2 A1 A0 R/W DEVICE ADDRESS Figure 3. Slave Address Bits BUS RELEASE DELAY (TRANSMITTER) SCL FROM MASTER 1 BUS RELEASE DELAY (RECEIVER) 8 9 DATA OUTPUT FROM TRANSMITTER DATA OUTPUT FROM RECEIVER START ACK SETUP (≥ tSU:DAT) ACK DELAY (≤ tAA) Figure 4. Acknowledge Timing tHIGH tF tLOW tR tLOW SCL tSU:STA tHD:DAT tHD:STA tSU:DAT tSU:STO SDA IN tAA tDH SDA OUT Figure 5. Bus Timing http://onsemi.com 5 tBUF CAT24C256 WRITE OPERATIONS (within the selected page). The internal Write cycle starts immediately following the STOP. Byte Write In Byte Write mode the Master sends a START, followed by Slave address, two byte address and data to be written (Figure 6). The Slave acknowledges all 4 bytes, and the Master then follows up with a STOP, which in turn starts the internal Write operation (Figure 7). During internal Write, the Slave will not acknowledge any Read or Write request from the Master. Acknowledge Polling Page Write Hardware Write Protection The CAT24C256 contains 32,768 bytes of data, arranged in 512 pages of 64 bytes each. A two byte address word, following the Slave address, points to the first byte to be written. The most significant bit of the address word is ‘don’t care’, the next 9 bits identify the page and the last 6 bits identify the byte within the page. Up to 64 bytes can be written in one Write cycle (Figure 8). The internal byte address counter is automatically incremented after each data byte is loaded. If the Master transmits more than 64 data bytes, then earlier bytes will be overwritten by later bytes in a ‘wrap−around’ fashion With the WP pin held HIGH, the entire memory is protected against Write operations. If the WP pin is left floating or is grounded, it has no impact on the operation of the CAT24C256. The state of the WP pin is strobed on the last falling edge of SCL immediately preceding the first data byte (Figure 9). If the WP pin is HIGH during the strobe interval, the CAT24C256 will not acknowledge the data byte and the Write request will be rejected. Acknowledge polling can be used to determine if the CAT24C256 is busy writing or is ready to accept commands. Polling is implemented by interrogating the device with a ‘Selective Read’ command (see READ OPERATIONS). The CAT24C256 will not acknowledge the Slave address, as long as internal Write is in progress. Delivery State The CAT24C256 is shipped erased, i.e., all bytes are FFh. http://onsemi.com 6 CAT24C256 S T BUS ACTIVITY: A MASTER R T SLAVE ADDRESS BYTE ADDRESS A7 − A0 A15 − A8 SDA LINE S S T O P DATA P * A C K A C K * = Don’t Care Bit A C K A C K Figure 6. Byte Write Timing SCL SDA 8th Bit Byte n ACK tWR STOP CONDITION START CONDITION ADDRESS Figure 7. Write Cycle Timing S BUS T ACTIVITY: A MASTER R T BYTE ADDRESS A15 − A8 A7 − A0 SLAVE ADDRESS SDA LINE S DATA DATA n S T O P DATA n+63 P * * = Don’t Care Bit A C K A C K A C K A C K A C K Figure 8. Page Write Timing ADDRESS BYTE DATA BYTE 1 8 a7 a0 9 1 8 d7 d0 SCL SDA tSU:WP WP tHD:WP Figure 9. WP Timing http://onsemi.com 7 A C K A C K CAT24C256 READ OPERATIONS The address counter can be initialized by performing a ‘dummy’ Write operation (Figure 11). Here the START is followed by the Slave address (with the R/W bit set to ‘0’) and the desired two byte address. Instead of following up with data, the Master then issues a 2nd START, followed by the ‘Immediate Address Read’ sequence, as described earlier. Immediate Address Read In standby mode, the CAT24C256 internal address counter points to the data byte immediately following the last byte accessed by a previous operation. If that ‘previous’ byte was the last byte in memory, then the address counter will point to the 1st memory byte, etc. When, following a START, the CAT24C256 is presented with a Slave address containing a ‘1’ in the R/W bit position (Figure 10), it will acknowledge (ACK) in the 9th clock cycle, and will then transmit data being pointed at by the internal address counter. The Master can stop further transmission by issuing a NoACK, followed by a STOP condition. Sequential Read If the Master acknowledges the 1st data byte transmitted by the CAT24C256, then the device will continue transmitting as long as each data byte is acknowledged by the Master (Figure 12). If the end of memory is reached during sequential Read, then the address counter will ‘wrap−around’ to the beginning of memory, etc. Sequential Read works with either ‘Immediate Address Read’ or ‘Selective Read’, the only difference being the starting byte address. Selective Read The Read operation can also be started at an address different from the one stored in the internal address counter. S T BUS ACTIVITY: A MASTER R T S T O P SLAVE ADDRESS SDA LINE S P A C K SCL 8 SDA N O A C K DATA 9 8th Bit DATA OUT NO ACK STOP Figure 10. Immediate Address Read Timing S T BUS ACTIVITY: A MASTER R T S T A R T BYTE ADDRESS A15 − A8 A7 − A0 SLAVE ADDRESS SDA LINE S S T O P DATA P S * A C K * = Don’t Care Bit SLAVE ADDRESS A C K A C K N O A C K A C K Figure 11. Selective Read Timing BUS ACTIVITY: MASTER SLAVE ADDRESS DATA n DATA n+1 S T O P DATA n+x DATA n+2 P SDA LINE A C K A C K A C K Figure 12. Sequential Read Timing http://onsemi.com 8 A C K N O A C K CAT24C256 PACKAGE DIMENSIONS PDIP−8, 300 mils CASE 646AA−01 ISSUE A SYMBOL MIN NOM A E1 5.33 A1 0.38 A2 2.92 3.30 4.95 b 0.36 0.46 0.56 b2 1.14 1.52 1.78 c 0.20 0.25 0.36 D 9.02 9.27 10.16 E 7.62 7.87 8.25 E1 6.10 6.35 7.11 e PIN # 1 IDENTIFICATION MAX 2.54 BSC eB 7.87 L 2.92 10.92 3.30 3.80 D TOP VIEW E A2 A A1 c b2 L e eB b SIDE VIEW END VIEW Notes: (1) All dimensions are in millimeters. (2) Complies with JEDEC MS-001. http://onsemi.com 9 CAT24C256 PACKAGE DIMENSIONS SOIC 8, 150 mils CASE 751BD−01 ISSUE O E1 E SYMBOL MIN A 1.35 1.75 A1 0.10 0.25 b 0.33 0.51 c 0.19 0.25 D 4.80 5.00 E 5.80 6.20 E1 3.80 MAX 4.00 1.27 BSC e PIN # 1 IDENTIFICATION NOM h 0.25 0.50 L 0.40 1.27 θ 0º 8º TOP VIEW D h A1 θ A c e b L SIDE VIEW END VIEW Notes: (1) All dimensions are in millimeters. Angles in degrees. (2) Complies with JEDEC MS-012. http://onsemi.com 10 CAT24C256 PACKAGE DIMENSIONS TSSOP8, 4.4x3 CASE 948AL−01 ISSUE O b SYMBOL MIN NOM A E1 E MAX 1.20 A1 0.05 A2 0.80 b 0.19 0.15 0.90 1.05 0.30 c 0.09 D 2.90 3.00 3.10 E 6.30 6.40 6.50 E1 4.30 4.40 4.50 e 0.20 0.65 BSC L 1.00 REF L1 0.50 θ 0º 0.60 0.75 8º e TOP VIEW D A2 c q1 A A1 L1 SIDE VIEW L END VIEW Notes: (1) All dimensions are in millimeters. Angles in degrees. (2) Complies with JEDEC MO-153. http://onsemi.com 11 CAT24C256 PACKAGE DIMENSIONS TDFN8, 3x4.9 CASE 511AM−01 ISSUE A D A DETAIL A DAP SIZE 2.6 x 3.3mm E E2 PIN #1 IDENTIFICATION A1 PIN #1 IDENTIFICATION D2 TOP VIEW SIDE VIEW SYMBOL MIN NOM MAX A 0.70 0.75 0.80 A1 0.00 0.02 0.05 A2 0.45 0.55 0.65 A3 A2 A A1 0.25 0.30 0.35 D 2.90 3.00 3.10 D2 0.90 1.00 1.10 E 4.80 4.90 5.00 E2 0.90 1.00 1.10 e b L 0.65 TYP 0.50 0.60 A3 FRONT VIEW 0.20 REF b L BOTTOM VIEW e 0.70 DETAIL A Notes: (1) All dimensions are in millimeters. (2) Complies with JEDEC MO-229. http://onsemi.com 12 CAT24C256 PACKAGE DIMENSIONS SOIC−8, 208 mils CASE 751BE−01 ISSUE O SYMBOL MIN NOM A E1 E MAX 2.03 A1 0.05 0.25 b 0.36 0.48 c 0.19 0.25 D 5.13 5.33 E 7.75 8.26 E1 5.13 5.38 e 1.27 BSC L 0.51 0.76 θ 0º 8º PIN#1 IDENTIFICATION TOP VIEW D A e b q L A1 c END VIEW SIDE VIEW Notes: (1) All dimensions are in millimeters. Angles in degrees. (2) Complies with EIAJ EDR-7320. http://onsemi.com 13 CAT24C256 Example of Ordering Information (Note 12) Prefix Device # Suffix CAT 24C256 W Company ID (Optional) I −G Temperature Range Lead Finish G: NiPdAu Blank: Matte−Tin (Note 13) I = Industrial (−40°C to +85°C) E = Extended (−40°C to +125°C) Product Number 24C256 T3 Tape & Reel (Note 17) T: Tape & Reel 2: 2,000 / Reel (Notes 13, 14) 3: 3,000 / Reel Package L: PDIP W: SOIC, JEDEC X: SOIC, EIAJ (Note ) Y: TSSOP ZD2: TDFN (3 x 4.9 mm) (Note 14) ORDERING INFORMATION Orderable Part Numbers CAT24C256LI−G CAT24C256LE−G CAT24C256WI−GT3 CAT24C256WE−GT3 CAT24C256XI−T2 CAT24C256XE−T2 CAT24C256YI−GT3 CAT24C256YE−GT3 CAT24C256ZD2IGT2* (Note 16) CAT24C256ZD2EGT2* (Note 16) 10. All packages are RoHS-compliant (Lead-free, Halogen-free). 11. The standard lead finish is NiPdAu. 12. The device used in the above example is a CAT24C256WI−GT3 (SOIC−JEDEC, Industrial Temperature, NiPdAu, Tape & Reel, 3,000/Reel). 13. For SOIC, EIAJ (X) package the standard lead finish is Matte−Tin. This package is available in 2,000 pcs/reel, i.e., CAT24C256XI−T2. 14. The TDFN 3 x 4.9 mm (ZD2) package is available in 2,000 pcs/reel, i.e., CAT24C256ZD2I−GT2. 15. For additional package and temperature options, please contact your nearest ON Semiconductor Sales office. 16. Part number is not exactly the same as the “Example of Ordering Information” shown above. For part numbers marked with * there are NO hyphens in the orderable part numbers. 17. For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD8011/D. ON Semiconductor is licensed by Philips Corporation to carry the I2C Bus Protocol. ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. 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